Abstract

Although having already become a well-established water reclamation technology for reuse applications, there is still a need to further understand the capabilities of membrane bioreactor (MBR) technology in municipal water resource recovery applications requiring achievement of low effluent nitrogen and/or phosphorus concentrations. The aim of this document is to provide some useful guidelines for the design (and to some extent the operation) of MBR-based systems intended to meet stringent nutrient permits.

Various MBR biological nutrient removal (BNR) process configurations and unique features of MBR processes for nutrient removal are presented. Results from full-scale and pilotscale MBR BNR installations and comments from operating staff are used to evaluate process designs, technology performance statistics, and operating issues for achieving low effluent concentrations of nitrogen and phosphorus. These results indicate that low effluent nutrient goals can be achieved reliably with MBRs, however, this depends highly on the reliability and redundancy provided for each component of equipment such as pumps, blowers, and instruments. Key issues in the design and operation of successful MBR BNR applications were found to be: (i) control of dissolved oxygen (DO) within aeration tanks and recycle streams, (ii) strategically designing the system baffle walls to minimize DO carryover within the anoxic zone, (iii) control of chemical addition and design of injection point, and (iv) automation vs. manual operation of the system. Research needs identified from this evaluation of MBR BNR technology are also presented.